RN: Ignore Unused Rest Property Siblings

Summary:
Configures ESLint to allow unused variables that are the sibling of a rest property.

For example:

```
// It is okay for `type` to be unused.
const {type, ...coords} = data;
```

Reviewed By: TheSavior

Differential Revision: D8779952

fbshipit-source-id: 1f7b756a75d9363b85e05209ce2a9bb536c5d4da

.eslintrc

@@ -143,7 +143,7 @@
     "no-undef": 2,                   // disallow use of undeclared variables unless mentioned in a /*global */ block
     "no-undefined": 0,               // disallow use of undefined variable (off by default)
     "no-undef-init": 1,              // disallow use of undefined when initializing variables
-    "no-unused-vars": [1, {"vars": "all", "args": "none"}], // disallow declaration of variables that are not used in the code
+    "no-unused-vars": [1, {"vars": "all", "args": "none", ignoreRestSiblings: true}], // disallow declaration of variables that are not used in the code
     "no-use-before-define": 0,       // disallow use of variables before they are defined
 
   // Node.js